Fingernail touch sensors: spatially distributed measurement and hemodynamic modeling

Advancements on a new type of touch sensor for detecting contact pressure at human fingertips are presented. A fingernail is instrumented with miniature LEDs and photodetectors in order to measure changes in the nail color when the fingertip is pressed against a surface. The fingernail sensor allows the fingers to directly contact the environment without obstructing the human's natural haptic senses. Reflectance photoplethysmography is used to measure the pattern of nail color, i.e., the blood content under the fingernail. Hemodynamic modeling, based on actual fingertip anatomy and physiology, is used to investigate the dynamics of the change in blood volume at multiple locations under the fingernail. An optical model is created to relate the blood volume to the light intensity measured by the photodetectors. The theoretical analysis is verified through model simulation and experimentation using a prototype fingernail sensor.

[1]  Brenan J. McCarragher.  Force sensing from human demonstration using a hybrid dynamical model and qualitative reasoning , 1994, Proceedings of the 1994 IEEE International Conference on Robotics and Automation.

[2]  H. Harry Asada,et al.  Distributed Photo-Plethysmograph Fingernail Sensors: Finger Force Measurement Without Haptic Obstruction , 1999, Dynamic Systems and Control.

[3]  K. Toshimori,et al.  Artery anatomy and tortuosity in the distal finger. , 1991, The Journal of hand surgery.

[4]  W Siegenthaler,et al.  Red blood cell velocity in nailfold capillaries of man measured by a television microscopy technique. , 1974, Microvascular research.

[5]  E. Tsilibary,et al.  Putrescine: A Novel Inhibitor of Glycosylation‐Induced Cross‐Links in Laniinin , 1995, Microcirculation.

[6]  A Cliquet,et al.  A low-cost instrumented glove for monitoring forces during object manipulation. , 1997, IEEE transactions on rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society.

[7]  Myung Hwan Yun,et al.  An instrumented glove for grasp specification in virtual-reality-based point-and-direct telerobotics , 1997, IEEE Transactions on Systems, Man, and Cybernetics, Part B (Cybernetics).

[8]  R. Wolfram-Gabel,et al.  Vascular Networks of the Periphery of the Fingernail , 1995, Journal of hand surgery.

[9]  J D Coffman,et al.  Total and capillary fingertip blood flow in Raynaud's phenomenon. , 1971, The New England journal of medicine.

[10]  H. Harry Asada,et al.  Hand-in-glove human-machine interface and interactive control: task process modeling using dual Petri nets , 1998, Proceedings. 1998 IEEE International Conference on Robotics and Automation (Cat. No.98CH36146).

[11]  Hikaru Inooka,et al.  Determination of grasp forces for robot hands based on human capabilities , 1993 .

[12]  Makoto Shimojo,et al.  Measuring system for grasping , 1996, Proceedings 5th IEEE International Workshop on Robot and Human Communication. RO-MAN'96 TSUKUBA.

[13]  J. Webster,et al.  A silicon-based tactile sensor for finger-mounted applications , 1998, IEEE Transactions on Biomedical Engineering.

[14]  G. Foucher,et al.  Fingertip and nailbed injuries , 1993 .

[15]  M H FLINT,et al.  Some observations on the vascular supply of the nail bed and terminal segments of the finger. , 1956, British journal of plastic surgery.

[16]  Kuo-Wei Chang,et al.  Photo-plethysmograph nail sensors: for measuring finger forces without haptic obstruction: modeling and experimentation , 1999, Proceedings 1999 IEEE International Conference on Robotics and Automation (Cat. No.99CH36288C).

[17]  R G Radwin,et al.  A conductive polymer sensor for measuring external finger forces. , 1991, Journal of biomechanics.

[18]  Hildegard Rand Maricq.  Capillary Pattern in Familial Schizophrenics , 1963 .

[19]  David Zeltzer,et al.  A survey of glove-based input , 1994, IEEE Computer Graphics and Applications.

[20]  K. Toshimori,et al.  The distal venous anatomy of the finger. , 1991, The Journal of hand surgery.

[21]  R. Russell,et al.  Anatomy and physiology of the perionychium: a review of the literature and anatomic study. , 1980, The Journal of hand surgery.

[22]  Lin Wang,et al.  Progress towards a smart skin: fabrication and preliminary testing , 1998, Proceedings of the 20th Annual International Conference of the IEEE Engineering in Medicine and Biology Society. Vol.20 Biomedical Engineering Towards the Year 2000 and Beyond (Cat. No.98CH36286).

[23]  M. H. Flint.  Some observations on the vascular supply of the nail bed and terminal segments of the finger. , 1955 .